On July 28, 1917, the Gleneden, a British steamship privately owned, and the Giuseppe Verdi, an Italian steamship similarly owned, came into collision in the Gulf of Lyons, both being seriously damaged. November 7, 1918, the British owner of the Gleneden commenced a suit in rem in admiralty against the Giuseppe Verdi in the District Court for the District of New Jersey to recover damages occasioned by the collision, and a few days later the Italian owner of the Giuseppe Verdi commenced a like suit against the Gleneden in the District Court for the Eastern District of New York. The libel in each suit attributed the collision entirely to negligence of servants and agents of the owner of the vessel libeled, it being alleged that she was in their charge at the time. When the suits were begun the vessels were within the waters of the United States and each was within the particular district where libeled.

The proceedings in the suit against the Gleneden are of immediate concern. After process issued and the vessel was arrested, private counsel for the British Embassy in Washington, appearing as amici curiae, presented to the court a suggestion in writing to the effect that the process under which the vessel was arrested should be quashed and jurisdiction over her declined, because, as was alleged, 'the said vessel is an admiralty transport in the service of the British government by virtue of a requisition from the Lords Commissioners of the
[254 U.S. 522, 528]
Admiralty, and is engaged in the business of the British government, and under its exclusive direction and control and is under orders from the British Admiralty to sail from the port of New York on or about November 25, 1918, to carry a cargo of wheat belonging and consigned to the British government'; because the court 'should not exercise jurisdiction over a vessel in the service of a cobelligerent foreign government'; and because 'the British courts have refused to exercise jurisdiction over vessels in government service, whether of the British government or of allied governments, in the present war, and that by comity the courts of the United States should in like manner decline to exercise jurisdiction over vessels in the service of the British government.' An affidavit of the master of the vessel affirming the truth of much that was alleged accompanied the suggestion. The libelant, being cited to show cause why the suggestion should not be acceded to, responded by objecting that it was not presented through official channels of the United States and by denying that the facts were as alleged.

A hearing on the suggestion was had in which the libelant and counsel for the British Embassy participated-the latter only as amici curiae-and at which the owner of the Gleneden was represented informally, without an appearance. In the course of the hearing counsel for the libelant called on the others to submit proof in support of the allegations in the suggestion, particularly to produce the ship's articles and other instruments bearing on the suggested public status of the vessel, and the present the master for examination; but both the counsel for the British Embassy and the representative of the owner refused to do any of these things and insisted that the court was bound on the mere assertion of the claim of immunity to quash the process and release the vessel. The libelant produced the libel in the suit against the Giuseppe Verdi, depositions given in that suit by the
[254 U.S. 522, 529]
master and other officers of the Gleneden, a certificate from the customs officers in New York showing the report and entry of the Gleneden on her arrival, and other evidence, all tending measurably to show that the vessel was operated by her owner under a charter party whereby the owner was to keep her properly manned, furnished and equipped, was to assume any liability arising from negligent navigation, and was to bear all loss, injury or damages arising from dangers of the sea including collision. 'On all the facts' thus put before it, the court found that 'the Gleneden was owned by and was still in the beneficial possession of the Gleneden Steamship Company, Limited, a private British corporation, who through its servants, was in the actual control of the steamer and of her navigation, but engaged in performing certain more or less public services for the British crown under a contractual arrangement amounting to the usual or government form of time charter party.' The court 'decided accordingly that the Gleneden was not a public ship in the sense that she was either a government agency or entitled to immunity,' and the suggestion was overruled and an order was entered to the effect that the vessel would be released only on the giving of a bond by the owner securing the claim in litigation or a bond to the marshal conditioned for the return of the vessel when that could be done consistently with the asserted needs of the British government.

Afterwards, on November 29, 1918, the master, appearing specially for the interest of the owner and for the purpose of objecting to the arrest and detention of the vessel, interposed a special claim to the effect that the Gleneden Steamship Company, Limited, was the true and sole owner of the vessel and he as master was her true and lawful bailee; and also interposed therewith a peremptory exception to the jurisdiction of the court on the grounds taken in the suggestion on behalf of the British Embassy. This claim and exception concluded
[254 U.S. 522, 530]
with a prayer that the process be quashed and the vessel released. The exception was not set down for hearing and remains undisposed of. There was no appearance by either the owner or the master save as just stated; nor was there any appearance by the British government or by any representative of that government other than through the suggestion which counsel for the Embassy in Washington presented as amici curiae.

After filing the special claim and exception, the master applied to the Circuit Court of Appeals for the Second Circuit for writs of prohibition and mandamus preventing the District Court from exercising further jurisdiction and commanding it to undo what had been done; but the application was denied for reasons which need not be noticed now, 255 Fed. 24, 166 C. C. A. 352.

A few days later an arrangement was effected whereby an acceptable surety company undertook to enter into and file a stipulation for value in the usual form and in a sum to be named by the libelant, not exceeding $ 450,000, unless on an intended application to this court for a writ of prohibition the vessel should be held immune from the process under which she was arrested and detained. Following that arrangement, on December 10, 1918, the District Court entered the following order:

'On the annexed agreement for security, and consent of the proctors for the libelant herein, and the record herein it is

'Ordered that in order to prevent further delay and expense, the steamship Gleneden be and she hereby is allowed to proceed on her voyage and leave the physical custody of the marshal of the Eastern district of New York, provided, however, that this order does not and shall not be deemed to constitute any withdrawal of quashing of the writ of arrest; and it is

'Further ordered that all proceedings herein be stayed and special claimant's or libelant's time to file any other
[254 U.S. 522, 531]
or further papers herein be extended to and including the 23d day of December, 1918, and in case application is made for a writ of prohibition to the Supreme Court on or before December 23, 1918, all proceedings herein be stayed and the time of the special claimant or of the libelant to file any other or further papers herein be extended until ten (10) days after the entry and service of an order or decree on the final decision of the United States Supreme Court on the said writ of prohibition.'

The master thereupon asked leave of this court to file a petition for a writ of prohibition preventing the District Court from proceeding with the suit and from interfering with the Gleneden in any manner, and for a writ of mandamus directing that court to vacate the order made when the suggestion on behalf of the British Embassy was overruled and to enter an order releasing the vessel without requiring security; the grounds advanced in the petition being essentially a repetition of those embodied in the suggestion of counsel for the British Embassy. The requested leave was given, a rule to show cause was issued, a return was made by the District Judge, and counsel have been heard. Whether on the case thus made either of the writs should be granted is the matter to be decided.

The principal question sought to be presented-whether the Gleneden is such a public vessel of the British government as to be exempt from arrest in a civil suit in rem in admiralty in a court of the United States-is one of obvious delicacy and importance. No decision by this court up to this time can be said to answer it. The nearest approach is in the case of The Exchange, 7 Cranch, 116, where an armed ship of war, owned, manned and controlled by a foreign government at peace with the United States, was held to be so exempt. To apply the principle or doctrine of that decision to the Gleneden would be
[254 U.S. 522, 532]
taking a long step, and the present posture of this litigation is such that we find no occasion to consider whether there is proper warrant for taking it.

It is conceded that the Gleneden is not an armed ship of war, and that she is not owned by a foreign government, but by a private corporation. In a sense she may be temporarily in the service and under the control of the British government, but the nature and extent of that service and control are left in uncertainty by the proofs, although the facts evidently are susceptible of being definitely shown.

Prima facie the District Court had jurisdiction of the suit and the vessel (The Belgenland,
114 U.S. 355
, 368-369, 5 Sup. Ct. 860), and to call that jurisdiction in question was to assume the burden of showing what was in the way of its existence or exertion. Merely to allege that the vessel was in the public service and under the control of the British government as an admiralty transport was not enough. These were matters which were not within the range of judicial notice and needed to be established in an appropriate way. They were not specially within the knowledge of the libelant, nor did it have any superior means of showing the real facts. Thus from every point of view it was incumbent on those who called the jurisdiction in question to produce whatever proof was needed to sustain their challenge.

As of right the British Government was entitled to appear in the suit, to propound its claim to the vessel and to raise the jurisdictional question. The Sapphire, 11 Wall. 164, 167; The Santissima Trinidad, 7 Wheat, 283, 353; Colombia v. Cauca Co.,
190 U.S. 524
, 23 Sup. Ct. 704. Or, with its sanction, its accredited and recognized representative might have appeared and have taken the same steps in its interest. The Anne, 3 Wheat. 435, 445, 446. And, if there was objection to appearing as a suitor in a foreign court, it was open to that government to make the as serted
[254 U.S. 522, 533]
public status and immunity of the vessel the subject of diplomatic representations to the end that, if that claim was recognized by the Executive Department of this government, it might be set forth and supported in an appropriate suggestion to the court by the Attorney General, or some law officer acting under his direction. The Cassius, 2 Dall. 365, Fed. Cas. No. 7,743; The Exchange, 7 Charch, 116; Id., 16 Fed. Cas. 85, No. 8786; The Pizarro, 19 Fed. Cas. 786, No. 11,199; The Constitution, L. R. 4 P. D. 39; The Parlement Belge, L. R. 4 P. D. 129; s. c. L. R. 5 P. D. 197.

But none of these courses was followed. The suggestion on behalf of the British Embassy was presented by private counsel appearing as amici curiae, and not thorugh the usual official channels. This was a marked departure from what theretofore had been recognized as the correct practice (see cases last cited); and in our opinion the libelant's objection to it was well taken. The reasons underlying that practice are as applicable and cogent now as in the beginning, and are sufficiently indicated by observing that it makes for better international relations, conforms to diplomatic usage in other matters, accords to the Executive Department the respect rightly due to it, and tends to promote harmony of action and uniformity of decision. See United States v. Lee,
106
U.S. 196, 209
, 1 S. Sup. Ct. 240. Of course, the suggestion as made could not be given the consideration and weight claimed for it.

From all that has been said it is apparent that the status of the Gleneden, judged in the light of what was done and shown in the District Court, is at best doubtful and uncertain, both as matter of fact and in point of law. The jurisdiction of that court is correspondingly in doubt, for it turns on the status of the vessel. The suit is still in the interlocutory stage. The court may take up again the question of its jurisdiction. If it does, the inquiry may proceed on other lines and the facts may be brought out more fully than before. In addition, the question
[254 U.S. 522, 534]
may be re-examined in regular course on an appeal from the final decree.

The power of this court, under section 234 of the Judicial Code (Comp. St. 1211) to issue writs of prohibition to the District Courts, when proceeding as courts of admiralty, to prevent an unlawful assumption or exercise of jurisdiction, is not debatable. But this power, like others, is to be exerted in accordance with principles which are well settled. In some instances, as where the absence of jurisdiction is plain, the writ goes as a matter of right. Ex parte Phenix Insurance Co.,
118
U.S. 610, 626
, 7 S. Sup. Ct. 25; Ex parte Indiana Transportation Co.,
244 U.S. 456
, 37 Sup. Ct. 717. In others, as where the existence or absence of jurisdiction is in doubt, the granting or refusal of the writ is discretionary. In re Cooper,
143
U.S. 472, 485
, 12 S. Sup. Ct. 453; In re New York & Porto Rico Steamship Co.,
155
U.S. 523, 531
, 15 S. Sup. Ct. 183; In re Alix,
166 U.S. 136
, 17 Sup. Ct. 522. And see Ex parte Gordon,
104
U.S. 515, 518
, 519 S.; The Charkieh, L. R. 8 Q. B. 197.

Here the most that can be said against the District Court's jurisdiction is that it is in doubt; and in other respects the situation is such that we deem it a proper exercise of discretion to refuse the writ. Nothing need be added to show that the request for a writ of mandamus is on no better footing. In re Morrison,
147
U.S. 14, 26
, 13 S. Sup. Ct. 246; Ex parte Oklahoma,
220
U.S. 191, 209
, 31 S. Sup. Ct. 426; Ex parte Roe,
234 U.S. 70
, 34 Sup. Ct. 722